The role of landscape and history on the genetic structure of peripheral populations of the Near Eastern fire salamander, Salamandra infraimmaculata, in Northern Israel

Abstract

Genetic studies on core versus peripheral populations have yielded many patterns. This diversity in genetic patterns may reflect diversity in the meaning of "peripheral populations" as defined by geography, gene flow patterns, historical effects, and ecological conditions. Populations at the lower latitude periphery of a species' range are of particular concern because they may be at increased risk for extinction due to global climate change. In this work we aim to understand the impact of landscape and ecological factors on different geographical types of peripheral populations with respect to levels of genetic diversity and patterns of local population differentiation. We examined three geographical types of peripheral populations of the endangered salamander, Salamandra infraimmaculata, in Northern Israel, in the southernmost periphery of the genus Salamandra, by analyzing the variability in 15 microsatellite loci from 32 sites. Our results showed that: 1) genetic diversity decreases towards the geographical periphery of the species' range; 2) genetic diversity in geographically disjunct peripheral areas is low compared to the core or peripheral populations that are contiguous to the core and most likely affected by a founder effect; 3) ecologically marginal conditions enhance population subdivision. The patterns we found lead to the conclusion that genetic diversity is influenced by a combination of geographical, historical, and ecological factors. These complex patterns should be addressed when prioritizing areas for conservation.

Genetic diversity and gene flow decline with elevation in the Near Eastern fire salamander (Salamandra infraimmaculata) at Mount Hermon, Golan Heights

“…Thus, it seems that migration and dispersal of salamanders is possible through human-mediated landscape structures at low and medium elevations. Our local findings contradict the view that dispersal of S. infraimmaculata is limited through low elevations as found in the range of Galilee (Kershenbaum et al, 2014;Sinai et al, 2019).…”

“…Recent genetic population studies revealed a restriction of connectivity between populations in Galilee and Mt. Carmel, possibly driven by land use change, such as settlements and agriculture, and a decrease in genetic diversity towards the southern distribution limit (Blank et al, 2013;Sinai et al, 2019). But the dispersal and migration behaviour of S. infraimmaculata is also strongly restricted by low elevation and steep slope (Kershenbaum et al, 2014;Sinai et al, 2019).…”

The degree of spatial variation relative to temporal variation influences evolution of dispersal

“…Ants, for example, were reported to show local adaptation, even in marginal habitats at their northern range edge (Nguyen et al 2019). Fire salamanders could also adapt to environmentally extreme habitats which were connected to core zones and did show a high genetic diversity (Sinai et al 2019); similar results were found by Schiffers et al (2014).…”

Long-term population genetic dynamics of the invasive ascidian Botryllus schlosseri, lately introduced to Puget Sound (Washington, USA) marinas

“…This step was repeated three times to evaluate if the number of clusters is consistent. Population clustering should be used with caution due to the different assumptions of the programs (Sinai et al, 2019), therefore NetStruct was used as a third method for analyzing the population structure using the network theory (Greenbaum, Templeton, & Bar-David, 2015). After an initial run, the threshold was set between 0.2 and 0.4 and 999 permutations were carried out.…”